The present invention relates to a magnetic encoding apparatus for encoding information onto a magnetic stripe of a plastic card such as a credit card, an automatic teller machine card, or other sheet material such as fare tickets or passbooks. The magnetic stripe encoding is typically performed along with other card processing operations such as embossing or graphics applications.
Magnetic encoded stripes are widely used on credit cards and other cards. Mechanisms for encoding information onto the magnetic stripes are well known in the field. Such a mechanism is disclosed in U.S. Pat. No. 4,518,853 to Gabel et al. The Gabel et al. patent discloses an encoding apparatus in which a tiltable carriage moves the card along a transport path past an encoding apparatus. The Gabel et al. patent uses pinch rollers to exit the card from the mechanism and also includes a tiltable plate which opens to remove defective cards.
The pinch rollers used in the Gabel patent to exit the card from the encoding mechanism have the possibility of marking cards and may slip due to wear and the accumulation of debris around the periphery of the rollers. Verification is performed by the same encoding head requiring the motor and carriage to reverse so that the card can be backed up and passed by the head again. This reversal and second passage requires additional time and decreases throughput rates.
Prior devices for mounting magnetic heads so that the face of the head follows a card surface are unsatisfactory. Such a mounting device is disclosed in U.S. Pat. No. 4,585,929 to Brown et al. The Brown et al. patent discloses a mounting bracket which swivels and moves toward and away from a card to follow a card surface. The head mounts in a bracket which in turn mounts on a rotatable shaft requiring bearings which will wear and therefore not constrain axial movement of the encoding head. The mounting point does not secure and properly align the encoding head so that additional pins are required to align the bracket which wear and misalign. Other prior mounting brackets suffer from the same defects and a number of additional problems which inhibit the head from following a card surface. Many brackets do not pivot freely enough for a head to follow the card surface or pivot too far away from the face of the head so that the head cannot follow the card surface. Other brackets do not constrain the head enough allowing the head to become misaligned in the direction of reading or writing leading to encoder errors. Also, prior mounting brackets are wider than heads, thereby not allowing two heads to be mounted in close proximity to each other.
While transporting the card along the encoder transport path, it is important that the card is not tilted during travel. Prior methods of keeping the card straight used a leaf spring pressing the card upward. However, as a card passes over the end of the spring, the card has uneven pressure applied which does not correct card position as readily as even pressure and such a spring is subject to wear. Prior even pressure devices use a card rail swinging on a pair of supporting arms. The rail provides even pressure to the card along the entire rail, but for keeping the card straight, the arms must be parallel and equal in length. This requires precision parts which will become misaligned with the passage of time. Another problem is undesirable lateral movement of the card caused by excessive play in the arms.
The card must also be properly positioned at the beginning of encoding for encoding information at the correct starting position on the magnetic stripe. Prior methods of set up require a card to be run through an encoder for creating flux changes along the magnetic stripe. The magnetic stripe is then coated with a developer comprising an iron powder and a liquid carrier. The powder enables the flux changes to be studied under a microscope. By viewing through the microscope, the distance from the leading edge of the card to a start sentinel, indicating the starting point on the magnetic stripe for encoding, may be accurately measured. Adjustments for encoding are then made relative to the start sentinel position, and the process is repeated until the desired position is reached. This method is time consuming and requires a developer and a microscope.
The prior methods of setting current levels for writing and amplification levels for reading the magnetic stripe on cards are unsatisfactory. There are no methods for an encoder using a write head and a read head setting its own write current level or read amplification level. The use of the encoder apparatus for current level set up and read amplification level setup eliminates other test equipment such as an oscilloscope and saves time for running tests.
It is evident that a faster, more efficient encoding apparatus is required which is durable and low cost. The present invention solves these and other problems associated with encoding magnetic stripes on plastic cards.